A Nasa spacecraft has provided the first optical images of ice within shadowed craters on Mercury. It might seem curious that the closest planet to the Sun - where temperatures soar above 400C - could host water-ice. But some of the craters on this hothouse world are always shadowed from the Sun, turning them into cold traps. Read more

A NASA spacecraft studying Mercury has provided compelling support for the long-held hypothesis the planet harbors abundant water ice and other frozen volatile materials within its permanently shadowed polar craters. The new information comes from NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. Its onboard instruments have been studying Mercury in unprecedented detail since its historic arrival there in March 2011. Scientists are seeing clearly for the first time a chapter in the story of how the inner planets, including Earth, acquired their water and some of the chemical building blocks for life. Read more